CNN reports Fifty-seven inmates have died in riots at four prisons in western Brazil, . Officials told the Agencia Brasil news agency that 15 prisoners were found dead Sunday and another 42 Monday in the city of Manaus, the capital of the state of Amazonas. Many appeared to have been asphyxiated. The Ministry of Justice and Public Safety said it would send a task force to the region, while the state prison secretary also announced an investigation.